Separation of oxygeated compound with bisulfite adducts



DGC- 28, 1948 v. F. MICHAEL ETAL 2,457,257

SEPARATION OF OXYGENATED COMPOUND WITH BISULFITE ADDUCTS /1 A 0. In V; E n; d A I v] o u; A N E L L N u GU Il) n o w i n: Q

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bf, \1` /n venfors.' Lk g Vesta E Michael g v Scott W WaV/lns'r Paten! Agent Dec. 28, 1948.

V. F. MICHAEL ETAL SEPARATION OF OXYGENATED COMPOUND WITH BISULFITE ADDUCTS Filed Sept. 24, 1947 5 Sheets-Sheet 2 Patent A qen/ Dec. 28, 1948. v. F. MICHAEL ETAI. 2,457,257

SEPARATION OF OXYGENATED COMPOUND WITH BISULFITE ADDUCTS 3 Sheets-Sheet 3 Filed Sept. 24, 1947 mmf n .GMT

SEPARATION 0F OXYGENATED OUMPOUND WITH BISULFITE ADDUCTB Vesta F. Michael and Scott W. Walker, Tulsa,

Okla., assignors to Stanoliud Oil and Gas Company, Tulsa, Okla.. a corporation oi Delaware Application September 24, 1947, Serial No. 775,318

2 0 Claims.

'I'his invention relates to the recovery of organic oxygenated compounds from solutions thereof in organic-liquids. and more particularly to a method forsegregating, separating, and purifying alcohols, aldehydes, ketones, carboxylic -acids. :and phenolic compounds from mixtures thereof with hydrocarbons.

Our invention broadly comprises a novel method for segregating alcohols from solutions thereof in organic liquids by extracting the alcohols with an vaqueous solution o! aldehyde and ketonebisulte addition products, and subjecting the extract to a diierential heat treatment above the decomposition temperature of the ketone-bisulte addition products to separate therefrom a fraction containing the alcohols. By means of these steps, in combination with other operations as hereinafter set forth.- we are able to separate solutions of organic oxygenated-compounds into generically'dissimilar groups, from which the in.- dividualvcomponents may then be conveniently isolated.

Numerous methods for preparing organic oxygenated compounds have been devised and reported in the prior art. Many of the methods produce the desired products in substantially pure condition, or in such mixtures that separationis comparatively simple by conventional means. Other methods, however, are less selective', and tend to produce complex mixtures from which the isolation of pure components is exceedingly-dinicult. For example, the direct oxidation of natural gas or of other hydrocarbon gases is potentially one of the cheapest sources of oxygenated compounds, and the method has therefore y been studied extensively. The reaction products, however, are acomplex mixture of the theoretically derivable organic oxygenated compounds, the isolation of which has proved to be very diiilcult. As a further example, the so-called Fischer- Tropsch synthesis, wherein carbon monoxide and hydrogen are reacted in the presence of ajauitable catalyst, such as iron or cobalt, produces primarily hydrocarbons, but in addition a small yield of oxygenated compounds.

More recently, a new and improved process for the hydrogenation of carbon monoxide has been developed which permits the use of the fiuidizedcatalyst technique. The use of this new technique with a catalyst of suitable composition in combination with carefully chosen conditions of temperature, pressure, and space velocity gives not only much greater space-time yields, but also products of a more desirable boiling range and higher octane number. higher yields of oxygenated compounds are produced.

InI one embodiment of the new process, for example, Wherein reduced iron catalysts containing around 1% of an alkali-metal compound, such In addition, relatively 56 as potassium hydroxide or potassium iiuoride, are

used to hydrogenate carbon monoxide. a water layer containins up to 15% or more of oxygenated compounds, and a hydrocarbon layer containing upto 40% or more of oxvgenated compounds are loduced under the following approximate contions:

Temperature i300-650 F. Pressure 15o-300 lb./in., gagel Space velocity 12-20 cu. it. O0,

- measured at 60 F.

and one atmosphere, per pound oi iron per hour CO concentration in feed-- lil-20% by vol. Hz:CO ratio in feed.' 2-8 The two layers have been found to contain the following oxygenated compounds, and others: acetaldehyde, propionaldehyda' acetone, methanol, methyl acetate, butyraldehyde. ethyl acetate, ethyl methyl ketone, ethanol, n-propyl alcohol. methyl n-propyl ketone, n-butyl alcohol, ethyl butyrate, methyl n-butyl ketone, n-pentyl alcohol. n-decyl alcohol, higher aliphatic alcohols, acetic acid, propionic acid, butyric acid, 2methylbutyric acid, valerio-acid, 3-methylva1eric acid, 2-methylhexanoic acid, caprylic acid, capric acid, myristic acid, palmitic acid, stearic acid, phenol, and higher phenols. The hydrocarbons in the product comprise Virtually the entire` range of saturated and unsaturated hydrocarbons, from dissolved methane to high-melting waxes. The following table illustrates the daily4 output ot the maior oxygenated products from a plant employing the new process to produce 6,000 barrels per day v(42 lggilons per barrel) of gasoline-range hydrocarns:

- Aqueous phase Gai/day Acetaldehyde 4,247 Propionaldehyde 873 Acetone 5,170 Methanol Y 333 l Butyraldehyde 1,231 Ethyl methyl ketone l2,171. Ethanol 30,322 n-'Propyl alcohol.y 6,879 n.-Butyl alcohol 2,036 n-Pentyl alcohol 504 Acetic acid 8,609 Propionic acid 3,217 Butyric acid 1,579

Hydrocarbon phase `Aldehydes and ketones 3,964 Alcohols 4,492 Acids i It Iwill be obvious to those skilled in the art that the isolation of individual components from such a complex mixture would be exceedingly diilicuit by any known methods. Simple, direct, fractional distillation of either the hydrocarbon phase or the aqueous phase is not feasible because of the numerous multiple-component azeotropes that are known to exist among the various constituents. and because of the tendency oi certain of the compounds to react, decompose, or polymerize when such a mixture is exposed to elevated temperatures ior considerable periods of time. Moreover, the literature discloses no selective solvent or solvents capable of eii'ecting the separation of such mixtures into the individual components.

In this situation, a new and eii'ective technique for isolating the components of the water-soluble aqueous products has been devised, as described in the copending Michael application, Serial No. 748,295, illed May 15, 1947; but the recovery oi' the oil-soluble oxygenated products on a. large scale has been considered virtually impossible, and serious consideration has been given to the conversion or destruction of these compounds by means of solid catalysts at high temperatures to produce a liquid hydrocarbon product suitable for use as a motor fuel. Now, however, we have devised a unique, surprisingly simple, and effective technique, involving successive extractions and a dierential heating step, by which we are able to isolate a remarkably high proportion of the oil-soluble oxygenated products.

One object of our inventionl is to provide a method for separating and purifying mixtures oi organic oxygenatel compounds from mixtures comprised thereof. Another object of our invention is to provide a method for segregating mixtures of organic liquids comprising organic oxygenated compounds into generically dissimilar groups of compounds.4 A further object of our invention is to provide a process for recovering organic oxygenated compounds, such as alcohols. aldehydes, ketones, carboxylic acids, and phenolic compounds, from hydrocarbon solutions thereof, and in particular from hydrocarbon solutions resulting from the oxidation of hydrocarbon gases, or from the hydrogenation of -oxides of carbon, in particular carbon monoxide. Another object oi' our invention is to produce a hydrocarbon product relatively free ofroxygenated compounds. A still further object is to produce a motor fuel of relatively good odor and of improved stability with respect to antiknock rating. Other objects of ourifinvention, and its advantages over the prior art, will be apparent from the following description.

The term generically dissimilar groups of compounds occurring herein is to be understood as meaning groups having dissimilar chemical properties. Under this deiinition, alcohols and phenols are generically dissimilar groups: and ketones, aldehydes, and carboxylic: acid are others.

An important factor in the development of our process was the unexpected discovery that alcohols may be separated from organic solutions thereof by extraction with an aqueous solution immiscible therewith comprising one or more bisulilte addition products (adducts) of aldehydes and/or ketones, as disclosed in the copending Michael application, Serial No. 775,919, filed September 24, 1947. It was also discovered that alcohols, aldehydes, and ketones can be removed simultaneously from organic solutions by extraction with an aqueous solution of a mixture of a water-soluble bisulfite and bisulte addition products of aldehydes and/or ketones. We have now found unexpectedly that a fraction containing primarily alcohols and ketones cltn be liberated from an extract containing an alcohol, at least' one bisuliite-ketone adduct, and at least one bisuliite-aldehyde adduct by heating the extract above about 40 to 50 C.. but below about 80 C.. after which the aldehydes remaining in the extract can be regenerated and removed by steamdistillation, suitably at a temperature above about 80 C., or by treating the extract with an alkaline material or a strong acid.

By means of a process based on these phenomena, we are now able to make a substantially complete segregation of, for example, a hydrocarbon solution containing alcohols, aldehydes, ketones, carboxylic acids, and phenolic compounds by a process which may include the following steps:

1. Extraction of alcohols, aldehydes, and ketones from the hydrocarbon solution by use of an aqueous extractant solution comprising a watersoiuble blsulte, at least one ketone-bisuiiite addition compound, and at least one aldehyde-bisullite addition compound.

2. Heat treatment of the resulting aqueous extract above the decomposition temperature of the ketone-bisulilte addition compounds, but below the decomposition temperature of the aldehydebisulflte addition compounds, and separation of a fraction containing primarily alcohols and ketones. The separation may be eiected by stratification, by stripping with steam or an inert gas, or by extraction with a selective solvent, such as a light hydrocarbon, an ester, or an aliphatic ether.

3. Further heat treatment of the aqueous phase from step 2 above the decomposition temperature of the aldehyde-bisulte addition compounds, ordinarily above about 80 C., and separation of the liberated aldehydes by steam distillation or b y extraction with a suitable solvent.

.10v 4. Extraction of the hydrocarobn raillnate from 'water-soluble bisuliite.

step 1 with an aqueous solution of a mild alkali, such as sodium carbonate, to separate carboxylic acids.

5. Extraction of the hydrocarbon railinate from step 5 with an aqueous caustic solution, such as aqueous sodium hydroxide, to separate phenolic compounds.

Numerous modifications may conveniently be made in the basic process outlined above. For example: l

A. In step 1, the hydrocarbon solution may be extracted simply with an aqueous solution of a l Bisulte-car-bonyl compound adducts are first formed and are extracted into the aqueous phase; the adducts then effect the extraction of alcohols into the aqueous phase.

B. A strong acid or an alkaline material may be A added to the alcohol-depleted aqueous solution from step 2 to break down the -bisuliite addition products therein and to release the aldehydes.

C. Steps 4 and 5 may be combined by extracting the hydrocarbon rafiinate from step 1 with an aqueous caustic Solution, such as aqueous sodium hydroxide, to separate carboxylic acids and phenolic compounds together.

Our process is suitable for separating alcohols from solution in virtually any organic liquid that is not completely miscible with aqueous bisulte solutions and that is compatible with bisulfite adducts in the sense that it does not react substantially with or have any substantial tendency to destroy aldehyde-bisulfite and ketone-bisulte addition compounds. Among such organic liquids may be cited aliphatic hydrocarbons in general, such as pentanes, pentenes, hexanes, hexenes,

heptanes, heptenes, octanes, octenes, petroleum naphthas, and the like; alicyclic hydrocarbons,

and aldehydes and ketones in general, such as the e group sei'I forth above. A

Water-soluble bisulfites in general are suitable for use in step 1 of our process, including bisulfltes of alkali metals, specically lithium, sodium, potassium, rubidium, and cesium; alkaline-earth metals, .such as calcium, barium, and strontium; and ammonium and substituted ammoniums, such as methylammonium, diethylammonium, tri's(2- hydroxyethyl) ammonium, benzyltrimethylam-- monium, and the like; but owing to the lower cost and greater availability of potassium and sodium bisulfltes, we ordinarily choose to use the latter two.

In step 1, the extraction should be carried out within the pH range in which the bisulfite addition compounds with aldehydes and ketones are stable, ordinarily Ibetween about pH 2.2 and 8, and preferably 'between about pH 5 and 8. For this reason, the pH of the stream of extractant supplied to the extraction column in step 1 should be adjusted as required by addition of an alkaline material, such as sodium hydroxide, or an acidic material, preferably sulfur dioxide or sulfurous acid, or a buifering agent, such as an acid sodium 1 phosphate.

For the most -effective extraction of aldehydes and ketones from the organic phase in step 1,. the

aqueous bisulfite extracting solution contacting each increment of the organic phase should con'- tain a quantity of free bisuliite at least equivalent to the aldehydes and ketones in the organic-phase increment. Preferably, however, the free bisulflte should be present in at least slight excess, and we have found that 50 to 100%V excess or more may be employed ladvantageously to speed up the extraction and to reduce the size -of equipment required. s

The aqueous bisuliite extracting solution employed in step 1 may suitably contain a total bisulte concentration, including both free and bound bisulte, between about 3 and 25 weight-percent, calculated as the anhydrous bisulilte salt, and

preferably between about and 15 weight percent. Excessively high concentrations are difficult to work with, owing to their tendency 4to cause crystallization or gelling during the extraction step. On the other hand, very low concentrations would make it' necessary to employ excessive volumes of extractant.v For effective extraction of alcohols, the extractant solution should contain between about 1 and 20 weight percent of ketonebisulfite and aldehyde bisulfite adducts, and pli!- ketone-bisulte adducts act as solubilizers for the alcohols, causing them also to transfer. from the organic phase into the aqueous phase. This solubilizing effect depends, to some extent, on thel molecular weight of the aldehydes and ketones in the addition compound. Bisulilte addition products of aldehydes and ketones having a distribution of molecular weights similar to the distribution of molecular weights in the alcohols have .been found to be most desirable. Preferably, therefore, means should be provided for recycling a portion of the adduct streams from various points in our process, in addition to the regenerated bisulilte solutions, as detailed in the examples below. We have also found it advantageous to incorporate a limited quantity, suitably up to about ten percent, of Aa lower aliphatic alcohol, such as ethanol or methanol, or a Vquantity of a .hydrophilic "ester, such as ethyl acetate or' butyl acetate, in the bisulilte-adduct extractant solu'- tion used in step 1, in order to reduce the tendency ofthe adducts to precipitate and to permit the use Aof higher concentrationsI of adducts. To this end.

we may also recycle a portion of the step 1 extract directly to the step 1 extractant.

The term "hydrophilic ester is to be understood as referring to esters having a solubility in water greater than about 1 percent by weight.

The step 1 extraction may be carried out satisfactorily at temperatures as low as 0 C. or somewhat below, the lower limit being the temperature at which freezing of the solution or precipitation of solids therefrom takes place. The upper temperature limits vary somewhat, depending on the type and quantity of ketones present in the organic solution and in the aqueous extractant solution. Ketone-bisuliite addition products become increasingly unstable at temperatures above about 40 C.: ordinarily, therefore, the extraction temperature should not be 40 C. i

The aqueousv extract from stepl contains aldehydes and ketones in chemical combination and alcohols in solution. -The extract is subsequently heated -to a temperature above the decomposition temperature of the ketone-bisulfite adducts, ordinarily above about 40 C., but below the decomducts contained therein, ordinarilybelow about era'ply between about 10 and 15 weight percent.

The adducts may be added to the extractant stream entering e extractor, or they may be formed in lsitu odiiication A of step 1) by reaction of free bisulte with ketones and aldehydes present in the organic solution. The concentration of adducts is not critical, and may be varied somewhat, depending on the quantity of alcohols to be extracted, the temperature of extraction, and thev permissible quantity of non-alcoholic contaminants in the extract.

In the step 1 extraction, the aldehydes and ketones in the organic phase react with the bisulte, giving a product which transfersreadily' into the aqueous phase; and the aldehyde-bisuliite and 80 C.; and a fraction comprising primarily alcohols and ketones is separated. The alcohol and ketone mixture may be separated from the aqueous solution by stratification, or, if desired, by extraction with a selective solvent immiscible with said aqueous solution. Light hydrocarbons, such as propane, butanes, pentanes, hexanes, and the like; esters, such as ethyl acetate, butyl acetate. methyl butyrate. and the like; and aliphatic ethers, such as ethyl'ether, n-propyl ether. isopropyl ether, n-butyl ether, isoamyl ether, and the like,vare particularly suitable for this extraction.

The heat treatment to regenerate and separate aldehydes (step 3) is preferably carried out above about 80"A C. to accelerate `the release of the aldehydes from the comparatively stable aldehydebisulflte adducts. The heat treatment is preferably combined with a steam distillation operation to release and separate the aldehydes in a single step. Alternatively, we may heat vthe alcoholdepleted and ketone-depleted aqueous solution from step 2 and extract the released aldehydes therefrom at around 80 C. or above, using s olvents such as those employed in step 2, and opervolatilization losses.

substantially above about Subsequent processing of the various fractions produced in the above steps may be carried out according to -methods known in the art. Spe- :ically, fractional distillation, azeotropic distillation, and extractive distillation may be emsloyed for separating the individual components of the alcohol-ketone mixture obtained in step 2, and of the aldehyde mixture obtained in step 3, and for further purifying the various hydrocarbon raiiinate streams obtained in the process, containing diminished proportions of oxygenated compounds. The hydrocarbon raffinate streams may alternatively or additionally be contacted with active adsorption agents, such as silica gel or alumina to remove substantially all oxygenated compounds therefrom. The aqueous solution of carboxylic acid salts resulting from step 4 may be treated with a strong acid such as sulfuric acid to regenerate the carboxylic acids, and the acids may then be further processed, as by fractional distillation. The same procedure is suitable for further processing the aqueous solution of phenolates resulting from step 5.

Our invention will be more fully understood from the following specific examples:

Example I The following example illustrates the application of our invention to the processing of a hydrocarbon solution containing mixed alcohols, aldehydes, and ketones. The major process steps were two in number: a single batch-type extraction of the hydrocarbon solution with an aqueous bisuliite-adduet solution, and a single batch-type extraction with heptane at an elevated temperai ture.

The hydrocarbon product layer resulting from the reaction of carbon monoxide with hydrogen over a uidized-iron catalyst, as described above,

was washed successively with water to remove hydrocarbon phase were agitated minutes at -457 C. with 100 parts by volume of an aqueous blsulfite adduct solution prepared by mixing 525 parts by weight of heptaldehyde, 525 parts by Weight of methyl amyl ketone, 1120 parts by weight of sodium bisulte, and v7980 parts by weight of water. The phases were then separated and analyzed. The aqueous layer measured 104 parts by volume and contained 0.573 grammoles of alcohols per liter.

The aqueous phase was subsequently agitated 15 minutes at 70-75 C. with 100 parts by volume of heptane, and the layers were separated and analyzed.

The heptane layer measured 101 parts by volume, and contained 0.0378 gram-moles of alcohols per liter, together with 0.0175 gram-moles or carbonyl compounds, primarily ketones, per liter.

The aqueous raffinate was made alkaline and steam distilled, and from it were isolated 6.05 parts by weight of an organic layer having the following properties: y

Speciilc gravity, 20/4 C. 0.838 Refractive index, 20 C. 1.4123

Example II The following example illustrates a process utilizing our invention for the treatment of the hydrocarbon phase resulting from the reaction of hydrogen and carbon monoxide over an alkalipromoted iron catalyst under conditions chosen io yield a high conversion to organic oxygenated compounds. as dened above.

In a preliminary operation, the stream of product vapors resulting from the hydrogenation oi' carbon monoxide is condensed at least partially and separated into a gas stream, an oil stream, and a water stream. A convenient method for carrying out this separation is illustrated in Figure 1:

The product vapor stream flows through line I into heat interchanger 2, where the normally liquid constituents are condensed partially or completely, and the resulting mixture of gases, oil and water flows through line 3 into knockout drum 4. The gas stream emerges from the latter through line 5, and is successively passed upward through scrubbers 6 and 9. The liquids from the knockout drum iiow through line I3 into separator I4, where the phases are permitted to separate. The separator is vented to gas line 5 through line I5.

Into the top of scrubber 6, a stream of water may be introduced through line l. Preferably, however, a dilute aqueous solution of water-soluble fatty acids, such as the bottom stream obtained in topping the aqueous phase from separator I4, is fed into the top of scrubber 6. Substantially all of the water-soluble oxygenated compounds are removed from the gas stream in scrubber 6. Into the top of scrubber 9 is introduced a lean oil through line Il, suitably a. p0rtion of a hydrocarbon stream that has been partially or completely denuded of oxygenated compounds in a later stage of our process. Scrubber 9 may be by-passed by valve Ill if desired. The scrubbed gases, now virtually entirely free of oxygenated compounds, emerge from the top of scrubber 9 through line I2, and may be returned to process or otherwise disposed of.

By regulating the temperature within separator M, the distribution of oxygenated compounds between the oil and water phases may conveniently be controlled as desired. We have observed that the higher the temperature within separator I4, the lower the concentration of oxygenated compounds in the aqueous phase.

The oil phase from separator I4 is withdrawn through line I6 and combined with the bottoms emerging from scrubber 9 through line I1, and the mixture is passed through line I8 into the bottom of washer I9. The aqueous bottoms emerging from scrubber 6 through line 20 are introduced into washer I9 at an intermediate point, and into the top of washer I9 is introduced a stream of fresh water through line 2|. As the oil stream rises through washer I9, it is therefore scrubbed successively with a dilute aqueous solution of oxygenated compounds and then with fresh Water. Substantially all of the water-soluble oxygenated compounds are thereby removed from the oil stream, which emerges through line 22 and is then further treated according to the process of our invention, in order to segregate oil-soluble oxygenated compounds therefrom.

The water stream from separator I4 is withdrawn through line 24 and mixed with the aqueure 1) ows through line 22 into pump 23 (Figure 2) and from there through line 24 into extractor 25, where it rises countercurrent to a downwardflowing aqueous solution of sodium bisulflte and bisulte addition products of aldehydes and ketones at a temperature around C. The free sodium bisulte adds to the'aldehydes and ketones. giving products which are transferred into the aqueous phase; and the bisulfite addition compounds act as solubilizers for the alcohols, permitting them also to be transferred into the aqueous phase. Y

The aqueous extract emerges from the bottom of extractor through line v26 and valve 21 and flows through line 28 into heater 29. Therein, the stream is heated to a temperature between about 40 and 80 C., and is discharged through line 30 into hot separatml 3|. Vapors from the hot separator pass through cooler 82 into separator 33, from which any condensed liquid is recycled through line 30 to the inlet of heater 29|, and any liberated sulfur dioxide is vented through line to line 36, which carries recycle extractant back to extractor 25. Liberated alcohols and ketones form a separate phase in separator 9|, and are withdrawn through line 31, cooler 38. and line 39. The aqueous phase in separator 3|. containing. dissolved alcohols and ketones, is withdrawn through line and valve 4|, and is transferred by pump 42 through line 43, heater 04, and line 45 into vacuum stripper 46 at an intermediate point. Residual dissolved alcohols and ketones are stripped from the entering stream at a temperature below about 80 C. by reboiler 41. The alcohols, ketones, and water vapor are taken overhead through condenser 48 into separator 49, to which a vacuum source is connected through line 50. The aqueous phase from the separator is reiluxed to stripper 06 through line 5|, and the alcohol and ketone phase is withdrawn through line 52. The alcohol and ketone streams in lines 52 and 39 are combined and withdrawn through line 53 to storage or to further processing.

The alcohol-depleted and ketone-depleted solu.

tion of bisulflte addition products owing from the bottom of stripper 46 passes through line 54 and valve 55 into pump 56, by which it is transferred through line 51 into heater 58. The stream is heated therein to a temperature above about 80 C. and is discharged through line 59 into an intermediate point of stripper 60, equipped with reboiler 6|. In the stripper, aldehydes are released from combination with the bisulte, and are taken off overhead in admixture with water vapors through condenser 62 into separator I63. The aqueous phase from separator 63 is reuxed to stripper through line 64, and the waterinsoluble phase, comprising primarily aldehydes, is withdrawn through line 65 to storage or further processing, such as by fractional distillation. A stream of regenerated bisulfite solution emerges from the bottom of stripper 60 through line 56 and cooler 61, and is recycled to extractor 25 through line 58, line 69, pump 10, and line 36. Makeup bisulte is added to the recycled stream as required through line 1|, and the pH of the bisulfite stream is adjusted, preferably to between about 5 and 8, by addition of sodium hydroxide or sulfurous acid through line 12.

10 The ketone and aldehyde-bisulfite adducts that are required to solubilize the alcohols in extractor 25 are supplied to the regenerated bisulte solution entering the top of the extractor through line 30 by adding thereto portions of other streams from various points in the process. For example, a portion of the stream emerging from extractor 35 through line 29, containing the desired, adducts, plus free bisultes and alcohols, may thus lbe withdrawn through valve 13 and introduced through line 14 and line 69 into pump 10. Similarly, a portion of the aqueous stream emerging from separator 3| through line 40, containing aldehyde-bisulte adducts. dissolved adducts and free bisulilte, may be withdrawn through cooler 13, line 18, valve 80, line 8|, line 69, and pump 10.

Hydrocarbons from the top of extractor 25 flow v through line |0| (Figure 2) into pump |02 (Figure 3), and are transferred thereby through line |03 into the bottom of extractor |04, where they flow upward countercurrent to a downward-nowing aqueous 7 vpercent sodium carbonate solution, introduced through line |05. In this extractor, sodium salts of the carboxylic acids are formed, and are dissolved in the water phase. The aqueous solution flows from the bottom of extractor |04 through line |09, pumpv |01, line |03, heater |09, and line ||0 into stripper at an intermediate point. Dissolved hydrocarbons are stripped'out of the solution by reboiler II2 and are taken overhead in admixture with water vapor through condenser ||3 into separator ||4, from which the aqueous phase is recycled to the stripper and the hydrocarbon phase is withdrawn through pump ||5 and line IIB and combined with the hydrocarbon stream issuing from the top of extractor -|04 through line ||1. The stripped y water solution from stripper is withdrawn the acidiilcation is allowed to escape through vent f line |25. The acidifled liquid flows from the bottom of reactor |22 through seal line |28 into knockout drum |21, where any remaining gases are separated and vented through line |28. From the bottom of knockout drum |21, the liquid emerges through line |29 and is transferred by pump |30 through line |3| into extractor |82 at an intermediate point. Into the bottom of the extractor is introduced through line |33 a solvent for fatty acids, which ows upward through the downward-flowing aqueous stream and extracts the fatty acids therefrom. Suitable solvents are aliphatic ethers, such as isopropyl ether, butyl ether, and the like; aromatic hydrocarbons, such as benzene, toluene, and the like: esters, such as ethyl acetate, butyl acetate, methyl butyrate, and the like; and high-boiling wood-oil fractions.

y Through une |34 at the top of the coiumn is 1nvbottom 6 1 extractor |52 is discarded. -f The hydrocarbon streams in lines ||4 and components of the mixture. The exhausted aqueous vstream emerging through line |35 at the I1, containig'small proportions of phenolic compounds, are combined in line |31, and are transferred byT pump |35 through line |39 into extractor |45, where they ow upward countercurrent to a'downward-fl'owing aqueousl l0 percent sodiumhydroxide solution.. introduced through line |41; In -this extractor, sodium phenolates are formed, and are dissolved in the water phase. The aqueous solution'ilows from the bottom oi extractor |40 through line |42, pumpl |43, line |44, heater |45, and line |46 into stripper |41 at an intermediate, point. Dissolved hydrocarbons are strlped'out of the solution `by reboiler |48 and aretaken overhead in-admixture with water vapor through condenser |49 into separator I 50, from which the aqueous phase is recycled to the stripper` and the hydrocarbon phase is withdrawn through' line 5| and combined with the hydrocarbon'stream issuing from the top of extractor |45 through line |52.

The combined hydrocarbon streams, now containing only minor proportions of oxygenated compounds, ilow through line |53 into pump |54,

and are transferred thereby through line |55 into the bottom of washer |58. The hydrocarbons pass upward through the washer countercurrent to a stream of water, introduced at the `top through line |51, which scrubs out any dissolved or enti-allied caustic material. The wash water from the .bottom of the washer is discarded through line |58. The hydrocarbons emerge from.

v.fractional distillation.

The-stripped water solution from stripper |41 is withdrawn through line |80, cooler |5|, and line Land is then acidiiled, preferably with sulfuric acid, added through line |63. The acidined mixture ilows into an agitated reaction vessel |64, where, it is cooled by a stream of cold water |45 iiowing through jacket |65. The reaction vesselis'vented through line |51. The acidiiled liquid flows from the bottom of reactor |54 throughseal line |88 into knockout drum |69, where'any entrained gases are separated and vented through line |10. From the bottom of knockout drum |69, the liquid emerges through line |1| and is transferred by pump |12 through line |13 vinto extractor |14 at an intermediate point 'Into-the bottom of the extractor is introduced through line |15 a solvent for phenolic compounds, which iiows upward through the downward-flowing aqueous stream and extracts the phenolic compounds therefrom. Suitable solvents aref aromatic, naphthenic, and saturated aliphatic hydrocarbons, such as benzene. toluene, cyclohexane, methylcyclopentane, hexanes, and oct'nes. Through line |16 at the top oi the'column' isintroduceds4 stream of fresh water, which washesany entrained or dissolved inorganic acid fromthe extract. The washed extract, comprisingr-solvent and phenolic compounds, emerges through line |11 at the top of extractor |14, and is sent-to storage or to further processing to isolatethe various components of the mixture. The exhausted aqueous stream emerging through line H ljat the bottom of extractor |14 is discarded.

. )Vhile the foregoing examples illustrate the preferred forms of our invention, it will be understood that departure may be made therefrom within the scope of the speciiication and claims.

In general. it can be said that any modifications or, equivalents that would ordinarily. occur to those skilled in the art are to be considered as lying within the scope of our invention.

In accordance with the foregoing specification, we claim as our invention: A

1. In a process for separating an alcohol from an organic solution comprised thereof, the steps which comprise contacting said organic solution with an immiscible aqueous phase in the presence of at leastl one bisulte-ketone adduct and at least one blsulfite-aldehyde adduct; separating and withdrawing an aqueous extract; heating said aqueous extract to a temperature above the decomposition temperature of bisulilte-ketone adducts, but below the decomposition temperature of any blsulte-aldehyde adduct contained therein; and separating from the heated aqueous extract an organic mixture comprising said alcohol and any liberated ketone.

2. The process of claim 1 wherein said organic solution comprises primarily a hydrocarbon liquid.

3. The processl of claim 1 wherein said immiscible aqueous lphase comprises also a member selected. from the group consisting of hydrophilic esters and lower aliphatic alcohols.

4. The process of claim 1 wherein said organic solution is contacted at a. temperature between about 0 and 40 C.

5, The process of claim 1 wherein said organic solution is contacted at a pH between about 2.2 and 8.

6. The process of claim 1 wherein said bisulfite adducts have substantially the same molecularweight distribution as the alcohols present in said organic solution.

'1.'The process of claim 1 wherein said aqueous extract is heated to a temperature between about 40 and 80 C. to decompose bisulte-ketone adducts contained therein.

8. The process of claim 1 wherein a portion of the alcohol-depleted and ketone-depleted aqueous extract is recycled to said immiscible aqueous phase.

9. The process of claim 8 wherein the alcoholdepleted and ketone-depleted aqueous extract is subsequently heated above the decomposition temperature of any bisulflte-aldehyde adduct contained therein; and said aldehyde is then separated therefrom.

10. The process of claim 9 wherein at least a portion of the aldehyde-depleted aqueous extract is recycled to said immiscible aqueous phase.

1l. In a process for separating an alcohol from an organic solution comprising an alcohol, a ketone, and an aldehyde, the steps which comprise extracting said organic solution with an aqueous extractant solution immiscible therewith containing a water-soluble bisulfite; heating the resulting aqueous extract to a temperature above the decomposition temperature of bisulfite-ketone adducts in said aqueous extract, but below the decomposition temperature of any bisuliite-aldehyde adduct contained therein; and separating an organic mixture comprising said alcohol and said ketone.

12. The process of claim 11 wherein said watersoluble blsuliite is an alkali-metal bisullte.

13. The process of claim 11 wherein said watersoluble bisulilte is sodium bisulte.

14. The process of claim 11 wherein said aqueous extractant solution initially contains free bisulflte in a quantity at least equivalent to the uncombined carbonyl compounds contacted by said aqueous extractant solution.

15. In a process for separating an alcohol from an organic solution comprising an alcohol, a ketone, and an aldehyde, the steps which comprise extracting said organic solution with an aqueous extractant solution immiscible therewith comprising a water-solublebisulilte and bisuliite addition products of carbonyl compounds selected from the group consisting ol aldehydes and ketones; heating the'resulting aqueous extract to a temperature above the decomposition temperature oi.' blsuliite-ketone adducts in said aqueous extract, but below the decomposition temperature of any bisulilte-aldehyde adduct contained therein; and separating an organic mixture comprising said alcohol and said ketone.

16. The process of claim wherein the total bisulte, both free and bound, .present in said aqueous extractant solution is between about 3 and 25% by weight, calculated as the anhydrous water-soluble bisuliite.

17. The process of claim 15 wherein said aqueous extractant solution contains bisulilte addition products having substantially the same composition with regard to identity and relative proportions oi.' their constituent carbonyl compounds as said organic solution to be extracted therewith.

18. The process of claim 15 wherein said aqueous extractant solution contains bisulilte addition products resulting from said extraction.

19. In a process for separating and recovering generically dissimilar groups of organic oxygenated compounds from a heterogeneous liquid mixture comprising an alcohol, a ketone, an aldehyde. water, and a normally liquid hydrocarbon,

the steps which comprise separating a hydrocarbon phase from said liquid mixture at an elevated temperature; extracting said hydrocarbon phase with an aqueous extractant solution comprising a water-soluble bisulilte; heating the resulting aqueous extract to a temperature above the decomposition temperature o! insulate-ketone adducts in said aqueous extract, but below the de- -l composition temperature of any bisulilte-aldehyde adduct contained therein; and separating an organic mixture comprising said alcohol and said ketone.

20. In a process for separating and recovering generically dissimilar groups of organic oxygenated compounds from a hydrocarbon solution comprising an alcohol, a ketone, and an aldehyde, the steps which comprise extracting said hydrocarbon solution with an aqueous extractant solution comprising an alkali-metal bisulilte; separating said alcohol and said ketone from the resulting aqueous extract by extraction with a selective solvent at a temperature between about 40 and 80 C.; distilling the alcohol-depleted and ketone-depleted aqueous extract at a temperature above about C. to regenerate and separate said aldehyde therefrom; further extracting the hydrocarbon railinate from the initial extraction step with an aqueous solution of a mild alkali to remove carboxylic acids therefrom; and subsequently extracting the acid-depleted hydrocarbon railinate with an aqueous caustic solution to remove phenolic compounds.

VESTA F. MICHAEL. SCOTT W. WALKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,095,830 Ekstrom May 5, 1914 1,704,751 Luther et al May 12, 1929 2,080,111 Bump May 11, 1937 2,274,750 Soenksen et al Mar. 3, 1942 2,288,281 Huijser June 30, 1942 FOREIGN PATENTS Number Country Date 472,545 Great Britain Sept. 23, 1937 

